SUMMARY/ ABSTRACT The Research Experience and Training Coordination Core (RETCC) is organized around the principle that the skills needed for productive careers in environmental science include the ability to think creatively in a cross- disciplinary context, communicate effectively with a range of audiences, and appreciate the role of communities and their concerns as both motivators and beneficiaries of environmental research. Our Metals and Metal Mixtures: Cognitive Aging, Remediation and Exposure Sources (MEMCARE) Superfund Research Center (SRC) is studying metal mixtures in multiple inter-related contexts: (a) their impact on cognitive aging (as well as mechanisms of association) in both human and experimental models; (b) identification of critical exposure windows for later life cognitive decline; (c) characterization of exposure variability; and (d) development of innovative technologies for exposure remediation. In this context, RETCC will develop resources to supplement trainee research activities beyond individual projects to promote: 1) cross-disciplinary experience in environmental science; (2) enhanced development of communication and leadership skills; and (3) understanding of the wide-ranging impact of Superfund research and the implications of this context on professional and intellectual development. The key resource developed by the RETCC (in collaboration with our SRC Research Projects) is a series of cross-disciplinary lab exchanges (externships) and practicums. Other resources developed by this Core include a new seminar series, workshop, and, in conjunction with the Community Engagement Core (CEC) and Research Translation Coordinator (RT), community engagement, and research translation opportunities to complement research activities. CEC and RT activities are designed to enhance trainee communication skills, not only among scientific peers, but also among constituencies for which SRC activities resonate?for example, communities impacted by contaminants and government agencies tasked with contaminant remediation and regulation. In collaboration with the Data Management and Analysis Core (DMAC), RETCC will also facilitate opportunities for data science training, including participation in a course in reproducible science. The Core will facilitate trainee participation in grantee and professional meetings and associated leadership and professional networking opportunities. Finally, the RETCC will facilitate trainee access to professional development resources and nominate qualified trainees for NIEHS SRP-sponsored honors. We anticipate that more than 20 trainees will participate in our SRC (about 2/3 pre- doctoral and 1/3 postdoctoral), each working on SRC research for 2-4 years. RETCC is a central component of this SRC, uniting all trainees and their mentors with common goals and shared activities, both inside and outside of the classroom and laboratory. Every Project will have trainees, and every trainee will interface with RETCC-sponsored training opportunities multiple times each year. In this context, RETCC will foster development of scientists with the skills needed to engage in impactful future environmental science research.